Since updating to Sierra, why will my Time Machine drives not work?

[iMore Question]

ever since I update to Sierra on my Macbook Pro, I cannot back up to either of my Time Machine drives -- it sticks on "preparing backup" for hours until I finally just quit out of it.

 

[anon(9602380)]

Welcome to iMore.

Have you tried turning your external drives off and on again. Try physically unplugging the drives from your computer and attaching them again. Have you tried rebooting your computer? Some suggestions for you to try. If you need further assistance please sign up and become a member so we can help further.

 

[LPariseau]

I have tried all those things -- and I am a member of the forum so not sure why it doesn't show that for you. thanks anyway.

 

[anon(9602380)]

Try this.

1. Unplug external HDD from power and USB.
2. Restart Mac.
3. Plug HDD USB cable into Mac USB port.
4. Turn HDD power on.
5. Wait several seconds.

If no luck with above, can you check to see if you can see the drive in disk utility.

 

[LPariseau]

tried all of those things. and yes I can see the drive in disk utility. I ran permissions on it. Still nada. thanks for the suggestions though